The present invention, in some embodiments thereof, relates to an interactive nasogastric tube (NGT) system.
A NGT provides direct transfer of food and/or an active pharmaceutical agent (API) to the stomach; both food and API being alternatively referred to herein using the general term “nourishment”.
To provide a supply of nourishment, the nourishment is typically placed in a reservoir that is higher than the patient's stomach and passes into the stomach through the NGT under the influence of gravity.
In intermittent and/or supervised nourishment, the NGT is connected to a reservoir containing the nourishment and an electronic pump controls and/or measures dispensation.
An NGT, though providing life-giving nourishment, does not prevent aspiration in which gastric contents, including gastric acids and undigested food enter the lungs. The lungs aspirate the gastric contents during inspiration of air, resulting in devastating consequences, for example aspiration pneumonia and/or death.
The prevalence of aspiration pneumonia is estimated to be as high as 95% of NGT nourished patients, and the mortality rate is estimated to be as high as 62%. American gastroenterological association technical review on tube feeding for enteral nutrition. Gastroenterology 1995; 108:3-21.
Methods for detecting aspiration of gastric contents include colored nourishment and pH monitoring. In colored nourishment, green or blue food coloring is added to the nourishment entering the stomach via the NGT tube. The presence of food coloring in the mouth indicates that gastric contents have been expelled from the stomach and are being aspirated by the lungs.
In pH monitoring, a pH sensor in the lungs sets off a signal when the normal lung pH of 7.6 drops due to the presence of gastric fluid in the lungs which have a typical pH of less than 4. The accuracy of detecting aspiration with a pH sensor, however, may be significantly compromised in the presence of H2 blockers and/or antacids that typically raise gastric fluid pH.
In typical NGT systems, the NGT may be improperly positioned, herein malpositioned, during or following NGT placement; a common occurrence in patients having impaired consciousness and in infants. To confirm proper NGT positioning, a radiograph interpreted by a radiologist may be required several times a day for a single patient with impaired consciousness on NGT nourishment; while radiographic confirmation may be required as often as 12 times per day for an infant.
The frequency of radiographs makes it impractical, if not impossible, to request radiographic assessment of NGT position by the radiologist. Without the input of a radiologist, a malpositioned NGT may be misdiagnosed by the nurse as being properly positioned, resulting in danger of aspiration to the infant.
Patents to devices designed to prevent NGT aspiration include:
U.S. Pat. No. 3,734,094 which teaches an NGT including a heart and lung acoustic monitor;
U.S. Pat. No. 5,065,754 teaches an NGT including a ventilator having lung pressure sensors;
U.S. Pat. No. 6,935,339 teaches an NGT including a secretion suctioning device; and
U.S. Pat. No. 5,417,664 teaches an NGT including a filter to stop some movement of reflux.